Abstract: Chemistry is a highly abstract discipline that is taught and learned with the aid
of various models. Among the most challenging, yet a fundamental topic in general
chemistry at the high school level, is molecular geometry. This study focused on
developing exemplary educative curriculum materials pertaining to the topic of
molecular geometry. The methodology used in this study consisted of several steps.
First, a diverse set of models were analyzed to determine to what extent each model
serves its purpose in teaching molecular geometry. Second, a number of high school
teachers and college chemistry professors were asked to share their experiences on
using models in teaching molecular geometry through an online questionnaire. Third,
findings from the comparative analysis of models, teachers’ experiences, literature
review on models and students’ misconceptions, the curriculum expectations of the
Next Generation Science Standards and their emphasis on three-dimensional learning
and nature of science (NOS) contributed to the development of the molecular
geometry unit. Fourth, the developed unit was reviewed by fellow teachers and
doctoral-level science education experts and was revised to further improve its
coherence and clarity in support of teaching and learning of the molecular geometry
concepts. The produced educative curriculum materials focus on the scientific practice
of developing and using models as promoted in the Next Generations Science
Standards (NGSS) while also addressing nature of science (NOS) goals. The educative
features of the newly developed unit support teachers’ pedagogical knowledge (PK)
and pedagogical content knowledge (PCK). The unit includes an overview, teacher’s
guide, and eight detailed lesson plans with inquiry oriented modeling activities replete
with models and suggestions for teachers, as well as formative and summative
assessment tasks. The unit design process serves as a model for redesigning other
instructional units in science disciplines in general and chemistry courses in particular.